Yeh Y Y, Johnson R M
J Nutr. 1975 May;105(5):588-94. doi: 10.1093/jn/105.5.588.
Liver cytoplasm from either vitamin E-deficient or normal rats has been shown to suppress mitochondrial respiratory decline induced by microsomes in vitro. The present study is an attempt to identify cytoplasmic factor(s) responsible for this suppression. The effect of cytoplasm from both groups of animals could be removed by trichloroacetate precipitation, boiling, and dialysis against 0.3 M mannitol-o.1 mM Tris buffer, pH 7.4, but not by aging or extraction with isooctane. The addition of oxalacetate of alpha-ketoglutarate plus asparate to cytolplasm potentiated the suppressant effect. Dialyzed cytoplasm was not effective in depressing the respiratory decline. However, the addition of NAD, osalacetate, or alpha-ketoglutarate plus aspartate to dialyzed cytoplasm restored its ability to depress the respiratory decline. When oxalacetate or alpha-ketoglutarate plus aspartate was added to fresh cytoplasm, followed by dialysis, the effect of these compounds was not seen. These results suggest that cytoplasmic factor(s) required for suppression of the respiratory decline were enzymes of the malate shuttle and transamination, which are heat labile and trichloroacetate precipitable, plus the dialyzable metabolites that are associated with these enzymes in the generation of NAD in mitochondria.
已证明，来自维生素E缺乏或正常大鼠的肝细胞质在体外可抑制微粒体诱导的线粒体呼吸衰退。本研究旨在确定导致这种抑制作用的细胞质因子。两组动物的细胞质的作用可通过三氯乙酸沉淀、煮沸以及用0.3M甘露醇-0.1mM Tris缓冲液（pH 7.4）透析去除，但不能通过老化或用异辛烷提取去除。向细胞质中添加草酰乙酸、α-酮戊二酸加天冬氨酸可增强抑制作用。透析后的细胞质在抑制呼吸衰退方面无效。然而，向透析后的细胞质中添加NAD、草酰乙酸或α-酮戊二酸加天冬氨酸可恢复其抑制呼吸衰退的能力。当向新鲜细胞质中添加草酰乙酸或α-酮戊二酸加天冬氨酸，然后进行透析时，未观察到这些化合物的作用。这些结果表明，抑制呼吸衰退所需的细胞质因子是苹果酸穿梭和转氨作用的酶，它们对热不稳定且可被三氯乙酸沉淀，再加上在线粒体中与这些酶在生成NAD过程中相关的可透析代谢物。
